What If, Sabito Never Died (Demon Slayer AU)

Makomo

“Urgh! I still can't cut it!” Sabito had been trying to slice his boulder in half for about a month now. Still, he couldn't do it.

Urokodaki had given both of them a boulder each. He told them that if they manage to slice these boulders in half, he'll be convinced that they are ready for the Final Selection to become a demon slayer.

But no matter how hard they tried, they couldn't even scratch it once!

“Even the breathing is not working...” Sabito sighed, “Hey, Giyuu? How about yours?”

“I.... can't do it...” Giyuu said in a sorrowful tone.

Ever since Sabito had met Giyuu, he was always sorrowful about something.

“Do you ever smile..?”  Sabito asked.

“What's so funny? Why should I smile?”

“Still...What are you grieving for?”

“It's just... I think, it might have been better if...if I had died instead... Or, maybe I should have. But I was such a coward! I didn't even dared to step out of my hiding place...”

Sabito became angered for some reason. He slapped Giyuu on his cheek hardly such that he fell on the ground by the force of the slap and touched his cheek, which was red right where he was hit.

“S-Sabito?!”

“Don't say that you'd be better off dying...ever again!” Sabito shouted at Giyuu, “If you ever said that...we are done! We'll stop being friends! Your big sister was about to get married! Despite that, she hid you from the demon! That life she protected by sacrificing her own....that future she left for you... It's an insult to her if all that is going to waste!!! So you can't die!”

“Yes... I understand you... I won't say that again..”

“Good. You better not.”

Urokodaki was watching all this from a distance. He smiled to himself, however, his smile couldn't be noticed from under his mask.

However, the real problem was still there.
They still haven't sliced the boulder in half.

“Oh come on!!! I'm trying everything!!” Sabito had quite an agressive personality.. apparently.

“The trick is..to increase the capacity of your lungs.” They heard a female voice say.

“Who said that..?” Giyuu looked around.

They saw a girl wearing a flowery kimono. She also had a fox mask on the side of her head.

“...by filling your blood with lots of air, and increasing your heart rate...” she said, “You can be as strong as a demon while staying human.”

“Who are you?” they asked.

“The most important thing right now is... You have a boulder each to slice.” she said.

“How do you know?” asked Giyuu.

“I was orphaned by a demon years ago... Urokodaki adopted me and also taught me water breathing.” the girl replied, “I can tell .. because I had sliced the boulder in half.”

“You had..?”

“Train...until it kills you. Because when you get down to it, there's nothing else you can do.”

With that last sentence, she was gone. She disappeared from there the next moment.

As the girl had suggested them, they tried to increase their lung capacity and finally one day...

“We did it!! Now, we can go to the Final Selection and be demon slayers!!!”